Glue solution and process of manufacturing same



of producing the same.

Patented Feb. 9, 1932 RALPH H. PRICE, OF CHICAGO, ILLINOIS, ASSIGNOR BY ME SN E ASSIGNMENTS, TO GLUE RESEARCH CORPORATION, OF NEW YORK, N. Y, A CORPORATION OF NEW YORK GLUE SOLUTION AND YROCESS OF MANUFACTURING SAME 1N0. Drawing.

My invention relates to a new composition of matter andit has special reference to an improved glue solution and the process More particularly my invention relates to a new solution comprising glue, which solution possesses a slight tendency only to ell but yet contains a high concentration of glue. By means of my invention I am able to produce a glue solution having a relatively highglue content and which possesses a considerably'lower jelling point for a given concentration of glue than an ordinary water solution containing substantially the same 'percentage of the same grade of glue.

My present solution, as exemplified by the specific illustrative solutions of my invention hereinafter described, has only aslight tendency to form a jelly at 0 F. and it does not undergo bacterial decomposition under ordi nary conditions of .storage and use. When the solution of my present invention, as exemplified by the specific illustrative solutions hereinafter to be described, is applied to a surface, the solution dries veryquickly because of the relatively high content of volatile organic solvent. By reason of the greater fluidity of my glue solution under ordinary conditions of use, it appears to have more penetrating and spreading power than a water solution having substantially the same glue concentration. These advantages particularly obtain with my new glue solution when applied to wood, fabrics, paper or other absorbent materials.

The ordinary animal glues dissolved in water form viscous solutions which vary in fluidity with the concentration and other factors for the particular grade of glue used. Such glue solutions tend to form a elly upon standing at room temperature unless extremely dilute and, unless some preservative is added, putrefaction due to bacterial decomposition soon sets in which alters considerably the strength and other properties.

of the glue. In my present glue solution bacterial decomposition is substantially precluded and, therefore, my improved glue solution retains many of its-initial properties.

Other objects of my invention will be here- Application filed December 7, 1925. Serial No. 73,919,

inafter revealed and for a better understanding of my invention reference may now be had to the following description and the appended claim which define my invention.

My invention is applicable tothe production of glue solutions adapted to many in dustrial uses. The following procedure may be used to produce a solution especially adapted to wood finishing, Inasmuch as different grades of glue varying in viscosity, jell strength, acidity, etc. may be required for other uses of my improved solution, it is of course, to be understood that the proportions which I herein specify are not essential but may be varied in accordance with the requirements for which the glue solution isto be adapted.

As a specific illustrative solution of my invention, I may utilize a clear glue which gives no precipitate with ferric ammonium sulphate by the method of testing described below, which glue is of the commercial grade known as Glue Association grade 4-4 and which has a jelly test of substantially 85 grams or lower and a viscosity test of substantially 35 millipoises or lower, both of these tests being conducted in accordance with the oflicial methods of the National Association of Glue Manufacturers as pub lished in Industrial and Engineering Chemistry, vol. 16, No. 3, p. 310. This glue is soaked incold water in the proportion of substantially five parts of glue to four parts of water by weight. After the glue has swelled thoroughly, which will require only two or three hours if a ground glue is used, this mixture is heated in a water jacketed kettle r a sufficient period to produce a smooth solution. I mix in a separate vessel one part of glycerine and two parts of denatured ethyl alcohol by weight.

.For the proportions mentioned above, in still another vessel-I dilute five parts of denatured ethyl alcohol with two parts of water by weight. Having prepared these three solutions I now take three parts of the alcoholglycerine mixture and to it I'add slowly eight parts of the hot aqueous glue solution, while constantly stirring the mixture. This mixture comprising the various ingredients proportions with different glues, even though I above are by weight.

is then stirred with suflicient vigorv to produce a smooth solution and while still stirring I slowly add eight parts of the diluted alcohol. The solution is then strained or filtered carefully to remove therefrom any foreign matter. (It should now be and should re main quite fluid at room temperature and should be substantially free from lumps or flocculated material.) It is to be understood that the order of addition of the above substances may be changed and other modifica-' tions may be made in the above technique without departing from the spirit and scope' of this invention.

Glue is, not a simple chemical compound but a very complex mixture of protein compounds and other substances of a nitrogenous nature, which mixture varies widely in the commercial product. In view of this fact it may be necessary to slightly vary the above they'show the same j ell and viscosity tests. A satisfactory solution may be obtained with "any glue of the above descriptionby substituting for part of the alcohol an equal amount of water. All proportions given While a glue showing no precipitate with ferric ammonium sulphate, such as is specified in the illustrative solution given above, produces a thoroughly satisfactory solution it is to be understood that other glues not responding to this test can be used, although slight .modifications in the formula may be neceswater solution of ferric ammonium sulphate is made up to contain 10 grams of this salt per 100 grams of solution. The ferric ammonium sulphate mentioned is the crystalline salt containing 24 molecules of water of crystallization. When to 100 cubic centimeters of the above dilute aqueous glue solution is added 20 cubic centimetersof the ferric ammonium sulphate solution no precipitate, or at least only a faint turbidity, should ide-v velop, even on stirring, after allowing the mixtures to stand at about F. for 12 hours.

Throughout this specification and the claims it is to be understood that the word glue as used herein includes any commercial adhesive of animal origin, such as the alkaline casein glue composition as well as glue from fish, hides, bones, etc. his well known that commercial glues made from fish,

parts by volume of water. alcohol denatured in certain other Ways may be prepared using casein. Inasmuch as casein lacks uniformity in quality and cannot usually be purchased on such definite jell and viscosity specifications, as is the case with animal glues, the proportions given in the following example are to be under stood as being only approximate.

As an exampleusing casein, I take 50 parts of water and in it dissolve 3 parts of soda ash. To this is added slowly with stirring,-

28 parts of dry casein. The mixture is allowed to stand until the casein. has swelled somewhat and is then heated in a water jacketed vessel until a smooth solution is obtained. In a separate vessel, a mixture of equal parts of denatured ethyl alcohol and neutral 7 5% Turkey red oilis heated to approximately 120 F. and 16 parts of this warm mixture is added slowly with constant stirring to the alkaline casein glue mixture. More alcohol, first warmed to about 120 F., is now added.

With certain caseins which I have used, I have found it possible to add 50 parts of alcohol at this point without precipitation taking place in the finished solution. It will be understood, however, that because of the -great variation in the quality of commercial casein available it will be necessary to determine, for the casein to be used, just how much alcohol can be added without causing an undesirable precipitate in the finished product. All proportions in this example also are by weight.

F The alcohol which I have described above as being denatured ethyl alcohol is designated in the trade as"N umber 5 completely denatured alcohol and contains per 100.

partsby volume of ethyl alcohol, 2 parts by volume of methylalcohol, one fourth part by .volume of pyridine bases, one half part by volume of benzine and usually about l-6 be used if desired.

However, ethyl 'Sulphonated or water soluble vegetable or mineral oils, glucose or similar glue softemng substances, or mlxtures of these substances ormixtures of these substances with glycerine, with Turkey red oil or with both.

glycerine and Turkey red oil may be used in proper proportions in place of the glycerine or Turkey red oil specified in the above illustrative examples. Such ingredients provide a highly satisfactory solution for most purposes, although for certain uses it is posslble to prepare a useful but less satisfactory lue solution without them. As a specific il-- ustration of such a glue solution, applicant may utilize a clear glue of the commercial grade known as Glue Association grade 4-4 such as was used in the example hereinbefore cited in the specification. This glue is soaked in cold water in the proportion of substantially five parts of glue to four parts of water by weight. After the glue has swelled thoroughly it is heated in a water jacketed kettle until a smooth solution is obtained. In a separate vessel seven and one-half parts of denatured ethyl alcohol may be mixed with three. and one-half parts of water. This dilute alcohol is then added very slowly to the above concentrated aque ous glue solution while the'whole is rapidly and vigorously agitated. In this coating composition, the glue softening agent is absent.

Instead of denatured ethyl alcohol I may use, among others, the following water soluble organic solvents; methyl alcohol; iso propyl alcohol; other water soluble higher alcohols; acetone, and water soluble esters. I may also use water soluble mixtures of the above-mentioned solvents. When I use substantially water insoluble solvents, such as methyl acetate; ethyl acetate; other substantially water insoluble esters; turpentine; furfural or mixtures of these, I add thereto such of the above described water soluble organic solvents as will produce a resultant water soluble solvent. The relative proportions of these substances may be varied with the grade of glue chosen and the purpose for which this solution is to be used.

As stated above, one use to which my improved glue solution may be applied advantageously is in finishing wood. Under such circumstances, the glue solution may be applied with a pneumatic spray brush or by other means thereby producing an undercoat or liquid filler. When the glue solution drys, it is almost entirely insoluble in such solvents as are found in varnishes,paints, and in nitrocellulose lacquers. This insolubility minimizes the tendency for the lacquer or varnish to be drawn into the grain of the wood or into the texture of any similar absorptive material to which my glue solution may be applied. In this fashion, a considerable saving is effected in the number of required coats of finishing materials, such as lacquer or varnish. Since my glue solution dries very rapidily, it is usually possible to apply any subsequent coat or coats of finishing material within two or three hours or less after applying the last glue undercoat. This is highly advantageous in this art when this time interval between coats is comparedwith the time interval which usually has been required heretofore with-the former fillers and undercoats. 55 Another advantage possessed by my glue glue solution.

solution is that it. does not appreciably raise the grain of wood as is' done by the usual water solutions, as heretofore employed. Therefore sanding is eliminated in most cases althou h the surface may be sanded easily if desire Still another advantage possessed by my glue solution in the wood finishing art 1s that it effectively seals in the stain which may have been applied previously to the wood undergoing treatment. As a result, this prevents the solvents in the lacquer or varnish from dissolving the stain which process produces an unsightly appearance. At present, shellac is commonly used as a sealing coat to revent this so-called bleeding of the stam, but shellac is not always effective because of the partial solubility of the shellac in the usual lacquers or varnishes. Consequently, the stain may still bleed through the shellac coat to some extent, When my glue solution is used as a sealing coat for stained work, it is preferable not to sandpaper the coat because it is highly desirable to preserve the glue coat as a continuous unbroken film.

Another use to which my present glue solution may be put is to provide a good paste wood filler or plastic composition which is,

capable of hardening. When used for this purpose I mix with my glue solution finely pulverized silica or other inert filler material, and pigments or stain, if desired.

Another use to which my glue solution may be put is to adapt it as a binding substance for clay,'pigments or other materials in the manufacture of wallpaper or coated papers I where an adhesive material is desired'which will not require being kept warm continuouse 1y during use.

Because of the lesser tendency of my present glue solution to jell .at room temperature,

and its greater penetrating power for a given concentration of the-glue, my solution is a desirable adhesive for wood joining, for ply- Wood-and veneer manufacture, and in the manufacture of laminated or plastic molded products. Furthermore, the glue in my solution may be hardened and made relatively waterproof by treatment in the usual way with such hardening agents as formaldehyde,

paraformaldehyde, chromium saltsand the like and by the application of heat. Such a hardening treatment is of advantage in some of the above-mentioned applications for my When hardened and waterproofed in this fashion my solution may be i used as a finish coat for various materials such as wood, paper and thelike.

- While I have herein described my present invention and the process of manufacturing the same, as well as methods for using my new glue solution, it is to be understood that various modifications may be made therein without departing from the spirit and scope of the appended claim.

I claim:

A freely fluid sprayabl'e albuminoid coating composition comprising a non-Jelhng stable solution of substantially 29 parts of commercial glue substantially free from foreign acid reacting substances in'a solvent comprising substantially 33 parts by weight ofethyl alcohol and substantially 35 parts of water, and an amount equivalent to substantially one-tenth of the weight of the .glue of a glue plasticizing agent selected from the group consisting of glycerol and Turkey red oil.

In witness whereof I have hereunto subscribed my name.

. V RALPH H. PRICE.

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